Rotating shafts, such as those used in gas turbine engines, typically require bearings to support relatively moving or rotating components. Where light weight and minimum power loss from friction are required, ball and roller element bearings are common, and may be used to react both radial and thrust loads.
Individual bearings inevitably have a limited thrust capability. Thus two or more bearings may be arranged adjacent one another to share the thrust load in so-called “stacked” bearing arrangements. Nonetheless, it can be still be desirable to control and limit thrust loads, particularly in large high bypass ratio engines where the thrust loads can be significant.
A difficulty arises, however, in that it can be difficult for an engine operator to determine loads imposed on bearings in operation, leading to uncertainty with regard to service life and maintenance schedules.